EE, O2, Vodafone and Three are the four networks that actually own UK mobile masts. Almost every other SIM brand rents capacity from one of them. Choosing between the big four is really a coverage and contract decision, not a brand popularity contest.
This guide compares them on what you can check yourself: where the signal works, how MVNOs sit on each host, and how to judge total cost including mid-contract rises. It does not crown a national winner or quote prices that will be wrong next week.
Check coverage at home and work first. Then compare live deals on that host network, including budget brands that run on it. A cheap SIM on the wrong masts is worse than a slightly dearer plan you can actually use.
Best next step: open live SIM only deals and filter by network after you know which host covers you.
What actually differs
- →Coverage and indoor signal where you spend time. National averages hide dead spots.
- →5G reach and whether a given plan includes it. Not every SIM on a 5G network is a 5G plan.
- →Contract shape: 30-day rolling versus 12 or 24 months, plus any mid-contract price rise.
- →Extras you will use: EU roaming, Wi-Fi calling, tethering limits, and international minutes.
- →Handset deals versus SIM only. Owning your phone and buying a SIM is often cheaper. See SIM only vs phone contract.
EE, O2, Vodafone and Three in practice
EE is often strong on speed and 5G in towns, which is why many people default to it. That does not make it the right buy if another network is fine at your address and the live deal is better once rises are included. Browse EE deals.
O2 is the host behind giffgaff. If O2 works for you, a giffgaff goodybag can be the simpler rolling option, with the same radio network and different plan rules. Compare O2 deals with giffgaff and our giffgaff review.
Vodafone hosts VOXI, Lebara and Talkmobile, among others. Coverage is the shared part. Streaming extras, international minutes and credit checks are not. Start with Vodafone deals, then VOXI vs Lebara if you want a no-frills or international-calling angle.
Three hosts Smarty and iD Mobile. It can be excellent value where the signal is solid, and frustrating where it is not. Check your postcode before you chase a low headline price. See Three deals, Smarty and iD Mobile.
How to choose
- Run a coverage check for home, work and anywhere you rely on mobile data. Ofcom and each network publish checkers. Trust your own addresses over a UK-wide ranking.
- Read what an MVNO is so you know which budget brands share that host.
- Shortlist live plans on /mobile (and /phones if you need a handset). Filter to the host that covers you.
- Read price-rise wording before you commit. Our mid-contract price rises guide explains what to look for. A low month-one price on a 24-month contract can cost more than a rolling SIM.
- Switch with a PAC code if you want to keep your number.
What this is not
It is not a speed-test league table, and it is not a promise that one network never rises in price. Deal cards and network order pages are the source of truth for this week's price, data and rise clause. Use the comparison to shortlist, then confirm on checkout.
Compare live deals on the network that covers you
Filter today's SIMs by network, then check contract length and price-rise terms before you pay.
Compare SIM only deals →Frequently asked questions
Which UK mobile network is best: EE, O2, Vodafone or Three?
There is no single winner. The best network is the one that works where you live, work and travel, at a price you will still be happy with after any mid-contract rise. Check coverage for your postcode first, then compare live SIM only and phone deals rather than a national league table.
Do MVNOs use the same coverage as EE, O2, Vodafone and Three?
Often yes for the radio network they rent, with caveats. Brands such as giffgaff (O2), Smarty (Three), VOXI and Lebara (Vodafone) and others ride a host network. Speeds, 5G access and roaming can still differ from the host's own plans. See what an MVNO is, then confirm the host on the deal before you buy.
How should I compare these networks without stale prices?
Pick the host network that covers you, decide SIM only versus a phone contract, then open live deals and read contract length and price-rise terms on the order page. We do not hardcode monthly prices here because they change.
Is Three's coverage as good as EE's?
It depends on your area. Published national scores are not a substitute for a postcode check. Three can be strong in some places and weak indoors in others, and the same is true of every network. Use a coverage checker for the addresses you care about.
Can I switch between these networks and keep my number?
Yes. Text PAC to 65075, give the code to your new network, and they handle the switch. Our PAC code guide walks through the steps.
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